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The diagnostic accuracy of the cardiothoracic ratio on chest X-ray to detect left ventricular (LV) enlargement has not been well defined despite its traditional association with cardiomegaly. We aimed to determine whether the cardiothoracic ratio can accurately predict LV enlargement based on indexed linear measurements of the LV on transthoracic echocardiography (TTE). We included consecutive patients who had a TTE and a posteroanterior chest X-ray performed within 90 days of each other at a tertiary care center. LV size was determined by measuring the LV end-diastolic dimension (LVEDD) and LV end-diastolic dimension indexed (LVEDDI) to body surface area. The cardiothoracic ratio was calculated by dividing the maximum transverse diameter of the cardiac silhouette by the maximum transverse diameter of the right and left lung boundaries. 173 patients were included in the study (mean age 68 ± 15 years, 49.1% female). Mean cardiothoracic ratio was 0.56 ± 0.09, and the mean LVEDD and indexed LVEDDI were of 47 ± 8.6 mm and dimension of 27 ± 4.5 mm/m 2 respectively. There was no significant correlation between the cardiothoracic ratio measured on chest X-ray and either the LVEDD or LVEDDI measured on TTE (r = 0.011, p = 0.879; r = 0.122, p = 0.111). The ability of the cardiothoracic ratio to predict LV enlargement (defined as LVEDDI > 30 mm/m 2 ) was not statistically significant. The cardiothoracic ratio on chest X-ray is not a predictor of LV enlargement based on indexed linear measurements of the LV by TTE., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)

The management of asymptomatic patients with severe aortic regurgitation (AR) and preserved left ventricular (LV) systolic function remains controversial. We evaluated the predictive value of exercise stress echocardiography (ESE) in asymptomatic severe AR with preserved LV systolic function for identifying high risk patients who might benefit from early referral for surgery. Symptom-limited treadmill ESE was performed in 67 asymptomatic patients with severe AR (effective regurgitant orifice area > 30 mm 2 , regurgitant volume > 60 ml) and preserved LV systolic function without LV dilatation [ejection fraction (EF) ≥ 50% and LV end-systolic diameter ≤ 50 mm]. A post-exercise EF increase of > 4% was defined as presence of contractile reserve (CR). The primary outcome was defined as the composite of symptoms development, deterioration in LV function (EF < 50% in echocardiography) and aortic valve replacement (AVR) at follow-up. Operations performed within 60 days of ESE were excluded. Twenty-eight patients were CR (+) and 39 patients were CR (-). Compared with the CR (+) group, the CR (-) group was older (52.0 ± 14.0 years vs. 43.8 ± 10.6 years, p = 0.011) and had higher Ln N-terminal natriuretic peptide (NT-proBNP) [5.2 (4.5-5.7) vs. 4.1 (3.7-5.1), p = 0.001]. The CR (-) group showed lower exercise time than the CR (+) group (576 ± 159 s vs. 671 ± 108 s, p = 0.008). Otherwise, there were no differences in demographics and imaging data between the two groups. During a follow-up duration of 46 ± 23 months, the primary outcome occurred in 17 patients (25%) including development of symptoms (n = 9), new-onset LV systolic dysfunction (n = 1) and AVR (n = 7). Fourteen of 17 were CR (-) group patients. The survival rate during follow-up was significantly lower in the CR (-) group than in the CR (+) group of asymptomatic severe AR patients (log-rank p = 0.035). The absence of CR in ESE is independently associated with deterioration of symptoms or LV systolic function in asymptomatic patients with severe AR and preserved LV systolic function. It can further risk stratify asymptomatic patients with severe AR and preserved LV systolic function and may influence the optimal timing of AVR.

As cardiac magnetic resonance imaging (CMR) has become widely used for evaluation of myocardial viability after acute myocardial infarction, the additional value of CMR parameters for prediction of left ventricle (LV) remodeling has been receiving interest. The aim of the study was to investigate the additional predictive value of CMR parameters for LV remodeling after successful reperfusion of ST-segment elevation myocardial infarction (STEMI) using multiple predictive models. LV remodeling was defined as ≥20% increase in end-diastolic volume at 6 month follow-up echocardiography. Using multiple stepwise regression analysis, conventional risk model was classified as following; model 1 (clinical factors), model 2 (model 1 + angiographic factors), model 3 (model 2 + echocardiographic factors) and CMR-added model; model 4 (model 3 + CMR factors). Among 262 enrolled patients, 25.1% showed LV remodeling. There were significant increments of c-statistics from the predictive model 1 to model 3 (AUC; 0.675 [0.60-0.75], 0.708 [0.64-0.78], 0.756 [0.69-0.82], respectively. all p < 0.05). However, model 4, which added the CMR variables, did not show any increase in predictive value compared with model 3 (AUC; 0.763 [0.70-0.83] versus 0.756 [0.69-0.82], p = 0.11). During the 28.2 months of median follow up, the incidence of hospitalization for heart failure was significantly higher in the patients with LV remodeling (6.1% vs. 0.5%, p = 0.02). CMR parameters did not provide incremental predictive value above the assessment by conventional echocardiography-based risk model in patients with STEMI.

The purposes of this study were to evaluate the relationship between risk factors for cardiovascular disease (CVD) and cardiac mass and function on cardiac magnetic resonance imaging (MRI), and to investigate possible risk factors for silent myocardial infarction (SMI) in an asymptomatic Asian population. We included 647 asymptomatic subjects (485 males, mean age 54.8 ± 6.7 years; 162 females, mean age 55.2 ± 7.6 years) who underwent 1.5-T cardiac MRI during a health checkup. The association between biventricular functional parameters as evaluated on MRI and CVD risk factors was examined using multivariable regression and analysis of variance. The left ventricular mass-to-volume ratios were positively related to body mass index (β = 0.153, p < 0.001), systolic (β = 0.165, p = 0.001) and diastolic (β = 0.147, p = 0.002) blood pressure, triglyceride levels (β = 0.197, p = 0.006), and C-reactive protein levels (β = 0.130, p < 0.001), and were negatively related to estimated glomerular filtration rates (β = -0.076, p = 0.025). No significant relationship was present between ventricular parameters and the presence of SMI after adjusting for confounders. The prevalence (6.9 %, 7/101) of SMI in diabetics was significantly greater than that in non-diabetics patients (0.9 %, 5/546; confidence interval 1.739-12.848; p < 0.001). Traditional CVD risk factors are associated with ventricular mass, geometry and function in asymptomatic subjects. Silent MI may not independently influence ventricular mass and function and diabetes mellitus may contribute to the development of SMI.

To evaluate the feasibility of using coronary magnetic resonance angiography (CMRA) with stress-perfusion and delayed-enhancement MRI as a screening tool for the detection of coronary artery disease (CAD) in asymptomatic subjects. Three hundred and forty-one self-referred asymptomatic subjects were enrolled in this study. Cardiac MR imaging was performed using a 1.5-T scanner with a 32-channel cardiac coil. Coronary artery stenosis, regional wall motion abnormalities, myocardial perfusion abnormalities, and delayed myocardial enhancement were analyzed. The occurrence of new chest pain and cardiac events was assessed in 332 subjects (97.3 %) over an average 29 ± 6 months (range, 18-39 months) follow-up period. A total of 3296 (82.4 %) of 4000 coronary artery segments examined exhibited diagnostic image quality on combined whole-heart and volume-targeted CMRA. Combined MRI detected significant CADs in 13 (3.8 %) of 341 subjects. Among these, 11 subjects (84.6 %) had both coronary artery stenosis (≥50 % by diameter) on CMRA and stress-perfusion defects in corresponding areas. Five of the 13 subjects showed evidence of old myocardial infarctions on delayed-enhancement MRI. Three subjects (0.9 %) underwent percutaneous coronary intervention after CAD was detected on cardiac MRI. There were no cardiac events during the follow-up period in subjects who complied with follow-up. Normal stress-perfusion and delayed-enhancement MRI lead to excellent outcomes when used to predict future cardiac events in asymptomatic subjects. Coronary MRA correlates well with stress-perfusion MRI for detecting significant CAD and helps exclude CAD in asymptomatic individuals.

Left ventricular strain echocardiography is reported to be more sensitive in detecting myocardial ischemia than conventional transthoracic echocardiography (TTE). We evaluated the usefulness of 2D strain analysis for the assessment of acute chest pain in emergency department (ED). Patients presenting to ED with acute chest pain were recruited. Patients with ST-elevation myocardial infarction, known coronary artery disease (CAD), non-ischemic cardiomyopathy, or non-cardiac chest pain were excluded. The pretest probability of CAD and TTEs were evaluated in all patients. TTEs included visual assessments of regional wall motion abnormality (RWMA) and analysis of global and regional longitudinal strain (GLS and RLS). The diagnosis of CAD and the occurrence of cardiac events during 1 month after ED visit were reviewed. Cardiac events were observed in 25% of total 104 patients, and CAD was detected in 36% of 69 patients with coronary imaging tests. Compared to RWMA, RLS showed higher sensitivity (sensitivity/specificity = 64/89 vs. 92/77%) with similar diagnostic accuracy (79.7 vs. 82.6%, p = 0.791) for CAD. RLS also demonstrated better diagnostic performance than either GLS (sensitivity/specificity = 92/57%) or pretest probability (sensitivity/specificity = 72/64 %). Similarly, RLS had the higher predictive value for 1-month cardiac events. In multivariable analyses including pretest probability, LVEF, RWMA, cardiac enzyme, GLS, and RLS; only pretest probability (OR 1.91, 95% CI 1.22-2.99, p = 0.005) and RLS (OR 25.42, 95 % CI 1.84-342.04, p = 0.016) independently predicted CAD. Strain echocardiography appears to be effective in diagnosing CAD and predicting future events with high sensitivity and negative predictive value in acute chest pain patients visiting ED.

Pulmonary hypertension (PHT) is not uncommon in patients with aortic stenosis (AS) and portends a dismal prognosis. We attempted to determine the prevalence of PHT and to identify contributors to its development in patients with moderate or severe AS. A total of 189 patients were enrolled. Patients were divided into two groups according to the presence or absence of PHT, with a pulmonary artery systolic pressure cutoff value of 40 mmHg. Left ventricular (LV) systolic function was assessed by global longitudinal (LV-GLS), circumferential (LV-GCS) and radial (LV-GRS) strains on top of LV ejection fraction (LV-EF). The ratio of mitral E to septal mitral annular e' velocity (E/e') was calculated to estimate LV filling pressure. Fifty patients (26.5 %) had concomitant PHT. Patients with PHT had a higher prevalence of diabetes, a lower LV-EF, a higher E/e', a larger left atrial volume index, a smaller indexed aortic valve (AV) area, and a more reduced LV-GLS (all p < 0.05). However, LV-GRS and LV-GCS were similar in patients with or without PHT. On multivariate logistic regression analysis, LV-GLS and E/e' were independently associated with PHT, whereas LV-EF and indexed AV area were not. PHT complicating moderate or severe AS is commonly found and is independently associated with systolic and diastolic dysfunction assessed by Doppler and strain imaging, but not with LV-EF.

We sought to determine the relationship between white blood cell count (WBCc) and infarct size assessed by cardiovascular magnetic resonance imaging (CMR) in patients undergoing primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI). In 198 patients undergoing primary PCI for STEMI, WBCc was measured upon arrival and CMR was performed a median of 7 days after the index event. Infarct size was measured on delayed enhancement imaging and the area at risk (AAR) was quantified on T2-weighted images. Baseline characteristics were not significantly different between the high WBCc group (>11,000/mm(3), n = 91) and low WBCc group (≤11,000/mm(3), n = 107). The median infarct size was larger in the high WBCc group than in the low WBCc group [22.0% (16.7-33.9) vs. 14.7% (8.5-24.7), p < 0.01]. Compared with the low WBCc group, the high WBCc group had a greater extent of AAR and a smaller myocardial salvage index [MSI = (AAR-infarct size)/AAR × 100]. The major adverse cardiovascular events (MACE) including cardiac death, nonfatal reinfarction, and rehospitalization for congestive heart failure at 12-month occurred more frequently in the high WBCc group (12.1 vs. 0.9%, p < 0.01). In multivariate analysis, high WBCc significantly increased the risk of a large infarct (OR 3.04 95% CI 1.65-5.61, p < 0.01), a low MSI (OR 2.08, 95% CI 1.13-3.86, p = 0.02), and 1-year MACE (OR 16.0, 95% CI 1.89-134.5, p = 0.01). In patients undergoing primary PCI for STEMI, an elevated baseline WBCc is associated with less salvaged myocardium, larger infarct size and poorer clinical outcomes.

The aim of this study was to determine the normal values for aortic pulse wave velocity (PWV) and distensibility using cine and phase contrast cardiac magnetic resonance imaging (CMRI) in patients without cardiovascular risk factors. PWV and distensibility are indispensible predictors of global and regional cardiovascular risk. Regional heterogeneity in aortic stiffness plays an important role in the pathogenesis of cardiovascular disease. Contrary to global estimates of aortic PWV that are commonly measured with tonometry, CMRI has emerged as an important method for estimating regional PWV and distensibility. A total of 124 Korean patients, aged 20-79 years and free of cardiovascular risk factors, were categorized by age decade. Using cine and phase contrast sequences, the cross-sectional area for distensibility and average blood flow were measured at four aortic levels: the ascending, upper descending thoracic, lower thoracic and abdominal aorta. Regional PWV was determined in four aortic segments: proximal, descending thoracic, abdominal aorta and across the entire aorta. Distensibility at the four levels of the aorta from the ascending to distal (4.4 ± 2.5, 4.0 ± 1.6, 5.2 ± 1.9, and 3.3 ± 1.7 × 10(-3) mm/Hg, respectively) was higher in women (P < 0.001) and decreased with age. The regional PWV was highest in the descending thoracic aorta and increased with age. The present study is the first to show the heterogeneity in aortic PWV and distensibility, as well to provide normal values for these parameters using CMRI in an Asian sample.

We sought to determine which contrast-enhanced magnetic resonance imaging (CE-MRI) parameter is the best predictor for left ventricular (LV) remodeling and clinical outcomes after ST-segment elevation myocardial infarction (STEMI). In 135 patients undergoing primary percutaneous coronary intervention (PCI) for STEMI, CE-MRI was performed at a median of 7 days after PCI. Echocardiography was performed soon after PCI and at a follow-up visit. LV remodeling was defined as an increase in end-diastolic volume index ≥20 % on follow-up echocardiography. Several CE-MRI parameters such as infarct size, transmurality, microvascular obstruction (MVO), and hemorrhagic infarction were tested using a 17-myocardial segment model. Optimal cut-off values were derived from receiver-operating characteristic curve (ROC) analysis. Twenty-eight patients (21 %) demonstrated LV remodeling. Although the addition of transmural necrotic segment count, infarct size, and MVO segment count to clinical models improved the prediction of LV remodeling in multivariable regression analysis, transmural necrotic segment count had better incremental predictive value than other CE-MRI parameters. The aggregate consideration of infarct size (cut-off ≥25 %), transmural necrotic segment count (≥5), and MVO segment count (≥2) yielded better diagnostic performance than each of the individual parameters in ROC analysis (P < 0.01). In Kaplan-Meier curve analysis, patients with transmural necrotic segment counts ≥5 had a higher incidence of major adverse cardiac event than did those without. The transmural necrotic segment count is the most important predictor of LV remodeling and clinical outcomes. The combination of CE-MRI parameters including infarct size, transmural necrotic segment count, and MVO segment count appeared to increase reliability for predicting LV remodeling.

The clinical utility of cardiac magnetic resonance imaging (CMR) is growing and is being used predominantly as a means of measuring ventricular function. The normal reference range of ventricular function may vary based on age, sex and ethnicity. At present, most CMR reference values for healthy individuals have been reported from Western countries. The intent of this study was to investigate the normal CMR reference range for left ventricular (LV) and right ventricular (RV) parameters in healthy Koreans. Healthy volunteers between the ages of 20-70 years without any history of cardiovascular disease or associated risk factors were prospectively recruited to be a part of this study. A total of 124 patients were recruited for this study. Steady-state free precession pulse sequences were used to obtain the cine images for LV and RV volume analysis. All parameters were analyzed based on age and gender, and normalized to body surface area (BSA). LV volume, mass and cardiac output were significantly greater in males than in females. However, all of these parameters which are associated with BSA and gender differences disappeared when corrected for BSA. RV volume was less in females even after the data was normalized for BSA. LV and RV volumes normalized for BSA gradually decreased with greater age, whereas the ejection fraction increased with age, thus maintaining the stroke volume index and cardiac index. LV and RV volumes, mass and function values for a healthy population largely depend on BSA and should be evaluated after normalization by BSA. LV parameters show no difference based on gender, but RV volume is less in the female. Greater age is associated with less ventricular volume, suggesting the possibility of volume sensitivity in the elderly.

Hypertrophic cardiomyopathy (HCM) is a disease that typically has heterogeneous hypertrophy and dysfunction of the myocardium. Cardiac magnetic resonance imaging (CMR) can be used to accurately assess ventricular wall thickness and regional fibrosis. We investigated the effects of hypertrophy and fibrosis on the heterogeneity of regional and global myocardial function in HCM. Forty patients who were diagnosed with HCM were consecutively enrolled. Echocardiography and CMR with delayed hyper-enhancement imaging (DHE) was performed for each patient. Left ventricular (LV) regional and global longitudinal strain (SL(R) and SL(G)) were obtained by two-dimensional speckle tracking method on echocardiography. With CMR, regional myocardial wall thickness was measured, and the amount of DHE was calculated semi-quantitatively in each segment. Overall, 720 segments were analyzed. SL(R) was significantly decreased in the hypertrophied segments (thickness > 11 mm) and segments with DHE (P < 0.001). SL(R) was correlated with myocardial wall thickness (r = 0.47, P = 0.001) and amount of regional DHE (r = 0.39, P < 0.001). On multivariate analysis, regional LV wall thickness and amount of DHE were the only independent determinants of SL(R). SL(G) was associated with LV diastolic functional parameters in echocardiography, total DHE volume, and LV mass index. Total DHE volume and LV mass index were independent determinants of SL(G) on multivariate analysis. The extent of regional myocardial fibrosis is associated with regional myocardial function independently of morphological changes of the myocardium, and the correlation extended to global LV function. In this context, DHE may be a useful parameter to discover early myocardial dysfunction independently of LV hypertrophy.

To define causes and pathological mechanisms underlying differences in clinical outcomes, we compared the findings of contrast-enhanced magnetic resonance imaging (CE-MRI) between ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI). In 168 patients undergoing early invasive intervention for STEMI (n = 113) and NSTEMI (n = 55), CE-MRI was performed a median of 6 days after the index event. Infarct size was measured on delayed-enhancement imaging, and area at risk (AAR) was quantified on T2-weighted images. The median infarct size was significantly smaller in the NSTEMI group than in the STEMI group (10.7% [5.6-18.1] vs. 19.2% [10.3-30.7], P < 0.001). Although there was a trend toward a greater myocardial salvage index ([AAR - infarct size] × 100/AAR) in the NSTEMI group compared to the STEMI group (48.2 [30.4-66.8] vs. 40.5 [24.8-53.5], P = 0.056), myocardial salvage index was similar between the groups in patients with anterior infarction (39.6 [20.0-54.9] vs. 35.5 [23.2-53.4], P = 0.96). The NSTEMI group also had a significantly lower extent of microvascular obstruction and a smaller number of segments with >75% of infarct transmurality relative to the STEMI group (0% [0-0.6] vs. 0.9% [0-2.3], P < 0.001 and 3.0 ± 2.3 vs. 4.6 ± 2.9, P = 0.001, respectively). Myocardial hemorrhage was detected less frequently in the NSTEMI group than the STEMI group (22.6% vs. 43.8%, P = 0.029). In the multivariate analysis, baseline Thrombolysis In Myocardial Infarction flow grade 3 and hemorrhagic infarction were closely associated with ST-segment elevation (OR 0.32, 95% CI 0.13-0.81, P = 0.017; OR 5.66, 95% CI 1.77-18.12, P = 0.003, respectively). In conclusion, in vivo pathophysiological differences revealed by CE-MRI assessment include more favorable infarct size, AAR, myocardial salvage and reperfusion injury in patients with NSTEMI compared to those with STEMI undergoing early invasive intervention.

Whether the left ventricular (LV) mass index (LVMI) and LV volumetric parameters are associated independently with natriuretic peptide levels is unclear in hypertrophic cardiomyopathy (HCM). Therefore, we investigated which parameters have an independent relationship with N-terminal pro-B type natriuretic peptide (NT-proBNP) levels in HCM patients using echocardiography and cardiac magnetic resonance imaging (CMR). A total of 103 patients with HCM (82 men, age 53 ± 12 years) were evaluated. Echocardiographic evaluations included left atrial volume index (LAVI) and early diastolic mitral inflow E velocity to early annular Ea velocity ratio (E/Ea). LVMI, maximal wall thickness and LV volumetric parameters were measured using CMR. The median value of NT-proBNP level was 387.0 pg/ml. The mean NT-proBNP level in patients with non-apical HCM (n = 69; 36 patients with asymmetric septal hypertrophy, 11 with diffuse, and 22 with mixed type) was significantly higher than in those with apical HCM (n = 34, P < 0.001). NT-proBNP level was negatively correlated with LV end-diastolic volume (LVEDV) (r = -0.263, P = 0.007) and positively with LVMI (r = 0.225, P = 0.022) and maximal wall thickness (r = 0.495, P < 0.001). Among the echocardiographic variables, LAVI (r = 0.492, P < 0.001) and E/Ea (r = 0.432, P < 0.001) were correlated with NT-proBNP. On multivariable analysis, non-apical HCM, increased maximal wall thickness and LAVI were independently related with NT-proBNP. Severity of LV hypertrophy and diastolic parameters might be important in the elevation of NT-proBNP level in HCM. Therefore, further evaluation of these parameters in HCM might be warranted.

To evaluate the ability to identify right ventricular (RV) dysfunction, and to predict adverse outcomes of chest computed tomography (CT), we compared CT and echocardiography in acute pulmonary embolism patients. We analyzed 56 patients diagnosed by CT with acute pulmonary embolism, who underwent echocardiography within 48 h of CT scan from January 2004 to December 2008. From the CT scan, the ratio of RV diameter to left ventricular diameter (RVd/LVd), the presence of septal bowing and embolus location were determined. RVd/LVd (P < 0.001), septal bowing (P < 0.001) and proximal embolism (P = 0.016) were associated with echocardiographic RV hypokinesia. The odds ratio for adverse clinical outcomes was 19.2 for the combination of three CT parameters (RVd/LVd > 1, septal bowing, and proximal embolism), and 13.4 for RV hypokinesia (each P = 0.001). The positive predictive value (PPV) for adverse clinical outcomes for echocardiographic RV hypokinesia was 55.0%, and the negative predictive value (NPV) was 96.2%. The three-parameter combination predicted adverse clinical outcomes with a PPV of 54.5%, and a NPV of 94.1%. CT parameters including RV dysfunction were significantly associated with poor outcomes. Rapid risk stratification of patients with acute pulmonary embolism based on chest CT appears to be comparable with echocardiography, is clinically reliable, and may be useful in guiding management strategy.

The absence of coronary artery calcification (CAC) has been used to as an indication to rule out significant coronary artery disease (CAD). However, diagnostic usefulness of 'zero calcium score criteria' as a decision-making strategy to rule out significant CAD as the etiology of acute chest pain has not been studied in depth, especially in Asian ethnicity. We prospectively enrolled 136 Korean patients (58% men, 56 ± 13 years) who presented to the emergency department (ED) with acute chest pain and non-diagnostic ECG. All patients underwent 64-slice CT for calcium scoring and coronary CT angiography (cCTA). We investigated the association of CAC with the presence of ≥50% CAD on cCTA and with a final diagnosis of an acute coronary syndrome (ACS). Ninety-two patients out of 136 (68%) did not show detectable CAC, and 14 out of these 92 without CAC (15%) had ≥50% CAD on cCTA. Sensitivity, specificity, positive predictive value and negative predictive value of zero calcium score criteria for the detection of ≥50% CAD were 0.66 (95% confidence interval, 0.50-0.80), 0.83 (0.74-0.90), 0.64 (0.48-0.77), 0.85 (0.75-0.91), respectively. Patients who had ≥50% CAD without detectable CAC were younger (P = 0.001), and had a higher prevalence of smoking (P = 0.048) as compared to patients with a degree of CAC. Most of the patients with ≥50% CAD of non-calcified plaque were younger than 60 years of age (79%, 11/14), however, 3 of them were older than 60 years of age. Forty-five patients (33%) were subsequently diagnosed as having ACS, and 38% (17/45) of them had no CAC. Zero calcium score did not necessarily guarantee the absence of significant CAD, even in patients older than 60 years, in Asian ethnicity presenting to the ED with chest pain.

Increasing coronary artery calcium scores (CACS) are independently associated with cardiac events. Recent advents in coronary computed tomography angiography (CCTA) have allowed us to better characterize individual plaque. Currently, it is unknown if higher CACS are likely to be associated with more calcified or mixed and heterogeneous plaque burden on CCTA. The study population consisted of 1,043 South Korean asymptomatic subjects (49 ± 10 years, 62% men) who underwent CCTA (64-slice MDCT). Plaques were classified on contrast-enhanced CCTA as non-calcified, mixed, and calcified on a per-segment basis according to the modified American Heart Association classification. The majority of the study participants had no coronary calcification (n = 866, 83%), whereas CACS> 0 was observed in 177 participants (17%). Only 40 (5%) participants in absence of CACS had exclusively non-calcified plaque, whereas 10 (1.2%) had significant coronary artery disease. With increasing CACS, study participants were more likely to have exclusively mixed or combination atherosclerotic plaques (P = 0.001). Among individuals with CACS 1-10, the prevalence of at least two coronary segments with mixed plaques was 4%, increasing up to 18 and 41% with CACS of 11-100 and >100. The respective prevalence of ≥2 coronary segments (calcified plaques) with increasing CACS were 6%, 16 and 26% (P = 0.01) and of non-calcified plaques were 6%, 6 and 11% (P = 0.71). In multivariable adjusted analyses, those with CACS >100 were 7.17 times (95% CI: 1.36-37.68) more likely to have ≥2 coronary segments with calcified plaque comparing with CACS 1-10. On the other hand the respective risk was higher for presence of ≥2 segments with mixed plaques (odds ratio: 15.81, 95% CI: 3.14-79.58). Absence of CAC is associated with a negligible presence of any atherosclerotic disease as detected by CCTA in asymptomatic population. A higher CACS is more likely to be associated with heterogeneous coronary plaque (combination of calcified, non-calcified, and mixed plaques), and appears to be more strongly associated with a higher burden of mixed plaque.